Question 152Refrigeration & AC - 1st Asst/Chief

The correct answer is A) The expansion valve would hunt excessively, alternately starving and over feeding the evaporator coil. If the replacement valve cage is oversized at 5 tons compared to the original 1/2 ton rating, the expansion valve will not be able to properly regulate the flow of refrigerant to the evaporator coil. The oversized valve cage will cause the expansion valve to "hunt" or cycle excessively, resulting in alternating periods of starving and over-feeding the evaporator coil. This hunting behavior will lead to inconsistent superheat and poor performance of the refrigeration system. The other answer choices are incorrect because: B) is incorrect as the oversized valve cage would cause problems, C) and D) are incorrect as the evaporator would experience both starvation and over-feeding, not just one or the other.